noun

• (historical) The ceremony of dressing a boy in trousers for the first time.
  "When boys left off skirts at about six or seven to put on breeches this was an occasion of minor ceremony which marked the next stage of growing up. By the 18th century breeching was taking place earlier, when a boy was three or four."
• (nautical) A rope used to secure a cannon.
• (equestrianism) A component of horse harness or tack, enabling the horse to hold back a vehicle.
  "Beside this, he has to learn to wear a collar, a crupper, and a breeching, and to stand still whilst they are put on; then to have a cart or a chaise fixed behind him, so that he cannot walk or trot without dragging it after him: and he must go fast or slow, just as his driver wishes."
• (slang) A beating or flogging.